I've read lots of forums etc but still wondering how you work out the SOI for a minor tune. Do you calculate it from the duration map? A simple explanation would be great.

Also if you wouldn't mind explaining how it should be setup i.e TDC is the ideal EOI, CORRECT? Advancing the SOI maps too much will cause negative torque as the EOI will be before TDC, but also if its retarded too much you get increased EGT temps and lose power CORRECT?